Esterquat, a quaternary ammonium compound, is known for use as a fabric softening molecule. It is typically formed when the reaction product of long chain (C12-C22 or C16-C18) fatty acids and a tertiary amine is esterified in the presence of an acid catalyst and subsequently quaternized to obtain quaternary ammonium salts. The final product is a mixture of mono-, di- and triester components.
Quaternary ammonium compounds exhibiting particularly good fabric softening performance and stability profiles are obtained from reaction of C12-C22 fatty acids or the hydrogenation products, usually containing some degree of unsaturation, having an iodine value range of 20-90.
Triethanol amine (TEA) tallow fatty acid esterquats have been one mainstay for fabric conditioners since the late 1990's. The triesterquat component of triethanol amine (TEA) esterquat has been generally held to have poor softening and fragrance delivery performance. The prior art has generally focused on efforts to enhance the diesterquat component which was claimed to maximize softening efficacy.
The costs of raw materials required for production of triethanol amine based esterquats such as fatty acids and dimethyl sulfate are increasing significantly in line with oil price increases. TEA esterquats are composed of mono-, di-, and tri-esterquats and mono-, di-, and tri-ester amines. This complicated chemistry results in emulsions that contain several types of emulsion structures, some of which do not effectively contribute to softening performance upon dilution in water during the rinse cycle of a fabric washing process because of their high solubility in water. This becomes particularly noticeable in fabric softening compositions in which the initial product active levels are reduced, resulting in less structure in the initial product emulsion.
Another difficulty of this esterquat system is that the complicated chemistry also makes it hard for a formulator to adjust or add other ingredients to the formulation: each emulsion structure reacts in its own way to the formula change and makes it very difficult for the formulator to balance all the different changes.
Another type of esterquat used in fabric conditioners is a methyl diethanol amine (MDEA) esterquat which has a less complicated chemical composition than TEA esterquats. The MDEA esterquat typically contains a blend of the monoesterquat and the diesterquat. Again, a mixture of mono- and diesterquats can cause reduced softening/fragrance delivery efficacy, stability, and formulation problems.
It is known that esterquat compositions having a high percentage of saturated fatty acids, which are known in the art as “hard” fatty acids, may suffer from processing drawbacks.
When used in fabric softening, esterquat compositions are required to provide not only good consumer perceived fabric softness while retaining good fragrance delivery but also good processability during manufacture.
There is therefore a need in the art for an esterquat composition, in particular for use as a fabric softening composition, which can have at least one of lower cost, a less complex formulation and/or manufacturing process, equivalent or higher softening and/or fragrance delivery performance, and consistent and predictable properties and performance as compared to known esterquat compositions.
There is, in particular, a need in the art for an esterquat composition for use in a fabric conditioner which can have a lower cost but at least a substantially equivalent softening and fragrance delivery performance as compared to known esterquat compositions for fabric conditioners.